1. Field of the Invention
The present invention relates to a fryer in which an oil discharge pipe is opened and closed to discharge cooking oil in an oil vat by opening and closing an oil discharge valve that is disposed in the oil discharge pipe, which extends from the bottom of the oil vat.
2. Description of Related Art
Conventionally, in fryers of this type, some cooking oil is removed together with the foods after cooking the foods, so in order to supplement lost cooking oil, the oil vats are periodically replenished with cooking oil. For the cooking oil, when oil such as lard, which is a solid oil at normal temperature, is replenished, although it remains solid immediately after being added, the lard gradually melts, and when it has liquefied its volume increases, resulting in an increase of the liquid level in the oil vat and frequently causing the liquid level to exceed the prescribed liquid level. By the liquid level of the cooking oil in the oil vat fluctuating between above and below a certain range of the prescribed liquid levels, the heating conditions of the foods change, and the result is a disparity in cooked foods, which is undesirable. Consequently, to counter such over-replenishing of cooking oil, it is necessary to open an oil discharge valve and discharge excess cooking oil from an oil discharge pipe into an oil tank in order to maintain the liquid level of the cooking oil at the prescribed liquid level.
However, by opening the oil discharge valve, too much cooking oil may be discharged, or if the oil discharge valve is mistakenly left in a state in which it is incompletely closed, the cooking oil can fall below the prescribed liquid level, the heating temperature of the foods by the cooking oil become too high, and the cooked foods result in being uneven, which is undesirable. Furthermore, there is also the possibility that an accident, such as the cooking oil catching fire, could occur by abnormally over-heating the cooking oil. Moreover, in the case of when cleaning the inside of the oil vats, there is the possibility of an accident caused by abnormal-overheating of the cooking oil when the opening/closing valve is opened in order to release the cooking oil from the oil vat and when the oil vats are mistakenly heated.
For that reason, among conventional fryers, there are those that stopped heating of the oil at the same time that the oil discharge valve is opened. With these fryers, however, each time the oil discharge valve is opened during cooking, the foods become poorly cooked because of inadequate heating, and it is necessary to discard these poorly cooked foods, resulting in an extreme waste of foods. On the other hand, in other fryers, a warning goes off the moment the oil discharge valve is opened. However, even if a warning is sounded, if the cook cannot take quick measures in response to the warning such as closing the oil discharge valve or stopping the combustion of the fryer because the cook is too busy or absent, there is the problem that inconveniences caused in conjunction with the reduction in cooking oil in the oil vat could not be properly addressed.
The present invention solves the aforementioned problems, and an object of the present invention is to provide a fryer that can prevent inconvenience such as the poor cooking of foods when an oil discharge valve operation is initiated and the cooking oil is discharged, for example, to adjust the liquid level of the cooking oil within the oil vat.
To achieve the above-mentioned object, in accordance with a first aspect of the present invention, a fryer includes an oil vat for containing cooking oil, a burning device for heating the cooking oil in the oil vat, an oil discharge pipe that extends from the bottom of the oil vat and that discharges the cooking oil from a discharge opening at its end into a tank, and an oil discharge valve disposed in the oil discharge pipe and is for opening and closing the oil discharge pipe, wherein the fryer is provided with an open valve detection means for detecting an open state of the oil discharge valve, a warning means for giving a warning according to a dictated result of an open state of the oil discharge valve by the open valve detection means, and a combustion stopping control means for controlling the burning device so that it stops combustion when a period of time that the open valve detection means has continuously detected that the oil discharge valve is open reaches a predetermined time. Here, the predetermined time means the time lag giving the fryer safety that heating an empty oil vat such as the cooking oil catching fire will not occur even if the cooking oil is discharged in a state wherein the oil discharge valve is completely open.
With this configuration according to the first aspect of the invention, to counter, for example, the over-replenishing of cooking oil, when the oil discharge valve is opened and excess cooking oil is discharged from the oil discharge pipe into the tank in order to maintain the liquid level of the cooking oil at the prescribed liquid level, the open valve detection means detects that the oil discharge valve is in an open state, and in response, the warning means gives a warning that the oil discharge valve is in an open state. Thus, even after the oil discharge valve has been operated, without interrupting preparation for food, it is possible to clearly identify from the warning that the oil discharge pipe is open and that the cooking oil in the oil vat is being discharged.
Furthermore, when the oil discharge valve continuously remains open for a predetermined time, combustion by the burning device is automatically stopped with controls from the combustion stopping control means. That is, the burning device is stopped after a prescribed time has passed, wherein the prescribed time is the time lag giving the fryer safety before heating an empty oil vat such as the cooking oil catching fire occurs, and thus heating an empty oil vat can be prevented before it happens.
Moreover, with the configuration according to a second aspect of the invention, in a fryer according to the first aspect of the invention, a time lag is provided between when the oil discharge valve is first opened and when cooking oil begins to be discharged from the oil discharge pipe, and wherein the warning means gives a warning immediately after the oil discharge valve starts to open. Therefore, an operator can quickly be aware that the oil discharge valve is open, and there is leeway before the oil discharge valve is closed. In particular, the discharge of the cooking oil can be minimized in the event that the oil discharge valve is accidentally opened.